1. Field of the Invention
The present invention relates to a cargo transfer apparatus, system, and method, each of which uses a tiered palletized rack to transport cargo or freight. Particularly, the present invention is directed to an improved apparatus, system, and method for the transport of cargo between road and rail using a tiered palletized rack that allows for efficient loading and unloading of cargo into railcars without a forklift entering into the railcar.
2. Description of Related Art
The use of railways to transport cargo has long been known in the art. Railway transport has the advantage that large amounts of cargo may be transferred on more or less direct routes between rail served origin and destination locations. This has long provided shippers with lower transportation costs due to the economies of scale rail service provides over road transportation alternatives.
However, a challenge with conventional rail transportation methods is that the current system lacks an efficient method for loading and safely transporting palletized freight. One method involves loading pallets into a shipping container, such as the standard 20 ft and 40 ft sea containers, and then loading the sea container onto a flat car for rail transport. However, this method obviously has the disadvantage of additional loading and unloading efforts associated with the container. More often than not, palletized freight is transported in box cars. However, this method also provides challenges in that the process of loading and unloading box cars with palletized freight is not efficient and often causes damage to the box cars or the freight as a result of the small area available to maneuver the pallet loading equipment, i.e., forklifts.
Another area where palletized freight presents challenges for transportation is in the refrigerated freight area. Refrigerated freight is often perishable, fragile, and difficult to stack for efficient use of space in railcars. Additionally, refrigerated freight requires particular spacing for shipment to allow for refrigerated air to be circulated around the freight to prevent hot spots, spoilage, etc. These requirements present substantial challenges to the conventional method of simply loading pallets into a railcar with a forklift and placing them on the floor of the railcar. One challenge in particular, aside from those noted above with regard to the confined space available for a forklift to operate in a railcar, is the efficient use of space for perishable items in refrigerated railcars, as perishable freight often cannot be double stacked. Thus, more than half of the available space in a refrigerated railcar (the space above the pallets set on the floor of the railcar) goes unused.
Double stacking of palletized loads may occur when the products are lighter weight and can be stacked without crushing or damaging the first tier of products or the products are not susceptible to weight related damage. In some instances, the products are crated or reinforced in some manner to provide the necessary support for two-tier loading. Another variation employs the use of a second tier platform, which is placed over the first tier of pallets after they have been loaded. Typically, two pallets of products are placed side by side at one end of the car. Then, second tier platform sections are placed over the first tier spanning the distance between the two sidewalls of the car. These sections are supported by structural members extending to the floor at the sidewalls of the car or attached directly to the sidewalls, thus eliminating any pressure on the bottom loads. This then enables a second tier of pallets to be loaded on the platform constructed above the first two pallets of products. However, current stacking methods risk damage to the cargo, either through human error where hand-stacking is involved, or through damage caused by the use of fork trucks to stack the cargo into the railcar.
The second tier sections utilized to span the distance between the side-walls may include simple 2×10 lumber, common metal floor grating, or more elaborate designs involving drop down sections which fold against the side of the car when not in use. Most of the perishable products shipped in thermally controlled railcars are hand-stacked to maintain uniform temperature control around the product. These products are also often sensitive to weight limitations due to the delicate nature of the products and packaging involved. An exception would be the shipment of frozen products where air circulation is not as critical and double stacking of pallets may be feasible. This is because the frozen products are less susceptible to load crushing. However, some palletized loads are being shipped either in a single-tier configuration inside the refrigerated freight car or by double-tiering the loads as previously discussed. This occurs when temperature control around the product is less sensitive (i.e., frozen products) or when load crushing is not an issue with the products involved. Cardboard slip-sheets are often used in place of common wood pallets to minimize load damage and minimize expense to the shipper. Pallets constructed of other materials and heights may also be used as required.
Two tier loading is accomplished in the same manner as described previously with palletized or slip sheeted loads handled individually in and out of the freight car with the use of manually operated fork trucks. However, this system has the disadvantages previously discussed. Thus, a need exists for an efficient system for palletized loading of a railcar that is adaptable to refrigerated or dry cargo, makes efficient use of the space in the railcar, and facilitates loading and unloading without damaging the cargo.